TorchTune (alpha release)

Introduction | Installation | Get Started | Design Principles | Contributing | License

Introduction

TorchTune is a native-Pytorch library for easily authoring, fine-tuning and experimenting with LLMs.

The library provides:

• Native-PyTorch implementations of popular LLMs
• Support for checkpoints in various formats, including checkpoints in HF format
• Training recipes for popular fine-tuning techniques with reference benchmarks and comprehensive correctness checks
• Integration with HuggingFace Datasets for training and EleutherAI's Eval Harness for evaluation
• Support for distributed training using FSDP from PyTorch Distributed
• YAML configs for easily configuring training runs
• [Upcoming] Support for lower precision dtypes and quantization techniques from TorchAO
• [Upcoming] Interop with various inference engines

The library currently supports the following models and fine-tuning methods.

Finetuning resource requirements

Note: These resource requirements are based on GPU peak memory reserved during training using the specified configs. You may experience different peak memory utilization based on changes made in configuration / training. Please see the linked configs in the table for specific settings such as batch size, FSDP, activation checkpointing, optimizer, etc used to obtain the peak memory.

NOTE: * indicates an estimated metric based on experiments conducted on A100 GPUs with GPU memory artificially limited using torch.cuda.set_per_process_memory_fraction API. Peak memory per GPU is as reported by nvidia-smi monitored over a couple hundred training iterations. Please file an issue if you are not able to reproduce these results when running TorchTune on certain hardware.

Installation

Currently, torchtune must be built via cloning the repository and installing as follows:

NOTE: TorchTune is currently only tested with the latest stable PyTorch release, which is currently 2.2.

git clone https://github.com/pytorch/torchtune.git
cd torchtune
pip install -e .

To confirm that the package is installed correctly, you can run the following command:

tune

And should see the following output:

usage: tune [options]  [recipe_args]
tune: error: the following arguments are required: recipe, recipe_args

Get Started

For our quickstart guide to getting you finetuning an LLM fast, see our Finetuning Llama2 with TorchTune tutorial. You can also follow the steps below.

Downloading a model

Follow the instructions on the official meta-llama repository to ensure you have access to the Llama2 model weights. Once you have confirmed access, you can run the following command to download the weights to your local machine. This will also download the tokenizer model and a responsible use guide.

> Set your environment variable HF_TOKEN or pass in --hf-token to the command in order to validate your access. You can find your token at https://huggingface.co/settings/tokens

tune download --repo-id meta-llama/Llama-2-7b \
--hf-token  \
--output-dir /tmp/llama2

Note: While the tune download command allows you to download any model from the hub, there's no guarantee that the model can be finetuned with TorchTune. Currently supported models can be found here

Running recipes

TorchTune contains recipes for:

• Full finetuning on single device and on multiple devices with FSDP
• LoRA finetuning on single device and on multiple devices with FSDP and .

To run a full finetune on two devices on the Alpaca dataset using FSDP:

tune --nnodes 1 --nproc_per_node 2 \
full_finetune_distributed \
--config full_finetune_distributed

The argument passed to --nproc_per_node can be varied depending on how many GPUs you have. A full finetune can be memory-intensive, so make sure you are running on enough devices. See this table for resource requirements on common hardware setups.

Similarly, you can finetune with LoRA on the Alpaca dataset on two devices via the following.

tune --nnodes 1 --nproc_per_node 2 \
lora_finetune_distributed \
--config lora_finetune_distributed

Again, the argument to --nproc_per_node can be varied subject to memory constraints of your device(s).

Copy and edit a custom recipe

To copy a recipe to customize it yourself and then run

tune cp full_finetune_distributed.py my_recipe/full_finetune_distributed.py
tune cp full_finetune_distributed.yaml my_recipe/full_finetune_distributed.yaml
tune my_recipe/full_finetune_distributed.py --config my_recipe/full_finetune_distributed.yaml

Command Utilities

tune provides functionality for launching torchtune recipes as well as local recipes. Aside from torchtune recipe utilties, it integrates with torch.distributed.run to support distributed job launching by default. tune offers everyting that torchrun does with the following additional functionalities:

1. tune will launch a torchrun job

2. and recipe arg can both be passed in as names instead of paths if they're included in torchtune

3. tune ls and tune cp commands provide utilities for listing and copying packaged recipes and configs

Design Principles

TorchTune embodies PyTorch’s design philosophy [details], especially "usability over everything else".

Native PyTorch

TorchTune is a native-PyTorch library. While we provide integrations with the surrounding ecosystem (eg: HuggingFace Datasets, EluetherAI Eval Harness), all of the core functionality is written in PyTorch.

Simplicity and Extensibility

TorchTune is designed to be easy to understand, use and extend.

• Composition over implementation inheritance - layers of inheritance for code re-use makes the code hard to read and extend
• No training frameworks - explicitly outlining the training logic makes it easy to extend for custom use cases
• Code duplication is prefered over unecessary abstractions
• Modular building blocks over monolithic components

Correctness

TorchTune provides well-tested components with a high-bar on correctness. The library will never be the first to provide a feature, but available features will be thoroughly tested. We provide

• Extensive unit-tests to ensure component-level numerical parity with reference implementations
• Checkpoint-tests to ensure model-level numerical parity with reference implementations
• Integration tests to ensure recipe-level performance parity with reference implementations on standard benchmarks

Contributing

We welcome any feature requests, bug reports, or pull requests from the community. See the CONTRIBUTING file for how to help out.

License

TorchTune is released under the BSD 3 license.